The present invention relates to a method for ascertaining a rotational speed parameter for determining a setpoint torque, to a device having means for ascertaining a rotational speed parameter for determining a setpoint torque, and to a drivetrain having a device having means for ascertaining a rotational speed parameter for determining a setpoint torque.
Methods for determining a setpoint torque for driving a drivetrain of a vehicle are known from the prior art. The propulsion torque or setpoint torque desired by the driver is ascertained from a characteristic map as a function of the accelerator pedal angle and a shaft rotational speed. Here, the shaft rotational speed corresponds to the rotational speed of the gearbox input shaft or for example the rotational speed of an internal combustion engine coupled thereto by means of a clutch.
Hybrid vehicles have multiple drive assemblies which individually or jointly generate the propulsion torque desired by a driver for accelerating the vehicle. The known method is also used in so-called parallel hybrid drive vehicles. In said topology of the drivetrain of the hybrid vehicle, both drive assemblies can be coupled to one another and are directly coupled to the gearbox input shaft. The rotational speed of the gearbox input shaft thus also corresponds to the rotational speed of the drive assemblies coupled thereto.
Hybrid vehicles exist which have drivetrain topologies in which the rotational speeds of the two drive assemblies are independent of one another. There is therefore no uniform rotational speed of both drive assemblies, such as is required for the known method for determining a setpoint torque.